对于下列的一组数字，筛选出能够分解成两个质数之和的，如9可以分解为2+7，而11则无法分解成两个质数之和
5, 6, 8, 13, 14, 15, 16, 17, 20, 21, 24, 26, 27, 30
Python源码：
list1 = [5, 6, 8, 13, 14, 15, 16, 17, 20, 21, 24, 26, 27, 30]
primes = []
for i in range(2, max(list1) + 1):
for j in range(2, i // 2 + 1):
if i % j == 0:
break
else:
primes.append(i)
for i in list1:
for j in primes:
if i - j in primes:
print("%d = %d + %d" % (i, j, i-j))
break
else:
print("%d不行" % i)